Overview

Osteoporosis, which means "porous bones," causes bones to become weak and brittle ? so brittle that even mild stresses like bending over, lifting a vacuum cleaner or coughing can cause a fracture. In most cases, bones weaken when you have low levels of calcium, phosphorus and other minerals in your bones

A common result of osteoporosis is fractures ? most of them in the spine, hip or wrist. Although it's often thought of as a women's disease, osteoporosis also affects a significant number of men. And compared with the number of women and men who have osteoporosis, many more have low bone density. Even children aren't immune. Yet it's never too late ? or too early ? to do something about osteoporosis. Everyone can take steps to keep bones strong and healthy throughout life.
 
Signs and symptoms
In the early stages of bone loss, you usually have no pain or symptoms.
But once bones have been weakened by osteoporosis, you may have signs and symptoms that include:

1. Back pain, which can be severe if you have a fractured or collapsed vertebra
2. Loss of height over time, with an accompanying stooped posture
3. Fracture of the vertebrae, wrists, hips or other bones

Causes
A full cycle of bone remodeling takes about two to three months. When you're young, your body makes new bone faster than it breaks down old bone, and your bone mass increases. You reach your peak bone mass in your mid-30s. After that, bone remodeling continues, but you lose slightly more than you gain. At menopause, when estrogen levels drop, bone loss in women increases dramatically. Although many factors contribute to bone loss, the leading cause in women is decreased estrogen production during menopause.

Your risk of developing osteoporosis depends on how much bone mass you attained between ages 25 and 35 (peak bone mass) and how rapidly you lose it later. The higher your peak bone mass, the more bone you have "in the bank" and the less likely you are to develop osteoporosis as you age. Not getting enough vitamin D and calcium in your diet may lead to a lower peak bone mass and accelerated bone loss later.

What keeps bones healthy
Three factors are essential for keeping your bones healthy throughout your life:

1. Regular exercise
2. Adequate amounts of calcium
3. Adequate amounts of vitamin D, which is essential for absorbing calcium

Risk factors

• Your sex. Fractures from osteoporosis are about twice as common in women as they are in men. That's because women start out with lower bone mass and tend to live longer. They also experience a sudden drop in estrogen at menopause that accelerates bone loss. Slender, small-framed women are particularly at risk. 
• Age. The older you get, the higher your risk of osteoporosis. Your bones become weaker as you age. 
• Race. You're at greatest risk of osteoporosis if you're white or of Southeast Asian descent. Black and Hispanic men and women have a lower but still significant risk. 
• Family history. Osteoporosis runs in families. For that reason, having a parent or sibling with osteoporosis puts you at greater risk, especially if you also have a family history of fractures. 
• Frame size. Men and women who are exceptionally thin or have small body frames tend to have higher risk because they may have less bone mass to draw from as they age. 
• Tobacco use. The exact role tobacco plays in osteoporosis isn't clearly understood, but researchers do know that tobacco use contributes to weak bones. 
• Lifetime exposure to estrogen. The greater a woman's lifetime exposure to estrogen, the lower her risk of osteoporosis. For example, you have a lower risk if you have a late menopause or you began menstruating at an earlier than average age. But if you have a history of abnormal menstrual periods, experience menopause earlier than your late 40s or have your ovaries surgically removed before age 45 without receiving hormone therapy, your risk is increased. 
• Eating disorders. Women and men with anorexia nervosa or bulimia are at higher risk of lower bone density in their lower backs and hips. 
• Corticosteroid medications. Long-term use of corticosteroid medications, is damaging to bone. These medications are common treatments for chronic conditions such as asthma, rheumatoid arthritis and psoriasis. If you need to take a steroid medication for long periods, your doctor should monitor your bone density and recommend other drugs to help prevent bone loss. 
• Thyroid hormone. Too much thyroid hormone also can cause bone loss. This can occur either because your thyroid is overactive (hyperthyroidism) or because you take excess amounts of thyroid hormone medication to treat an underactive thyroid (hypothyroidism). 
• Other medications. Long-term use of the blood-thinning medication heparin, the drug methotrexate, some anti-seizure medications and aluminum-containing antacids also can cause bone loss. 
• Breast cancer. Postmenopausal women who have had breast cancer are at increased risk of osteoporosis, especially if they were treated with chemotherapy. This isn't true for women treated with tamoxifen, which may reduce the risk of fractures. 
• Low calcium intake. A lifelong lack of calcium plays a major role in the development of osteoporosis. Low calcium intake contributes to poor bone density, early bone loss and an increased risk of fractures. 
  Medical conditions and procedures that decrease calcium absorption. Stomach surgery (gastrectomy) can affect your body's ability to absorb calcium. 
• Sedentary lifestyle. Bone health begins in childhood. Children who are physically active and consume adequate amounts of calcium-containing foods have the greatest bone density. Any weight-bearing exercise is beneficial, but jumping and hopping seem particularly helpful for creating healthy bones. Exercise throughout life is important, but you can increase your bone density at any age. 
• Excess soda consumption. The link between osteoporosis and caffeinated sodas isn't clear, but caffeine may interfere with calcium absorption and its diuretic effect may increase mineral loss. In addition, the phosphoric acid in soda may contribute to bone loss by changing the acid balance in the blood. If you do drink caffeinated soda, be sure to get adequate calcium and vitamin D from other sources in your diet or from supplements. 
• Chronic alcoholism. For men, alcoholism is one of the leading risk factors for osteoporosis. Excess consumption of alcohol reduces bone formation and interferes with the body's ability to absorb calcium. 
• Depression. People who experience serious depression have increased rates of bone loss.

When to seek medical advice
Early detection is important in osteoporosis. Consider your risk factors, then discuss your prevention strategy with your doctor. If you're a woman, it's best to do this well before menopause

Complications
Fractures are the most frequent and serious complication of osteoporosis. They often occur in your spine or hips ? bones that directly support your weight. Hip fractures, the second most common type of osteoporotic fracture, usually result from a fall. Although most people do relatively well with modern surgical treatment, hip fractures can result in disability and even death from postoperative complications, especially in older adults. Wrist fractures from falls also are common.

In some cases, spinal fractures can occur without any fall or injury simply because the bones in your back (vertebrae) become so weakened that they begin to compress. Compression fractures can cause severe pain and require a long recovery. If you have many such fractures, you can lose several inches of height as your posture becomes stooped

Prevention
Getting adequate calcium and vitamin D is an important factor in reducing your risk of osteoporosis. If you already have osteoporosis, getting adequate calcium and vitamin D, as well as taking other measures, can help prevent your bones from becoming weaker. In some cases you may even be able to replace bone you've lost.

The amount of calcium you need to stay healthy changes over your lifetime. Your body's demand for calcium is greatest during childhood and adolescence, when your skeleton is growing rapidly, and during pregnancy and breast-feeding. Postmenopausal women and older men also need to consume more calcium. As you age, your body becomes less efficient at absorbing calcium, and you're more likely to take medications that interfere with calcium absorption.

How much calcium and vitamin D?
Premenopausal women and postmenopausal women who use HT should consume at least 1,200 milligrams (mg) of calcium and a minimum of 400 international units (IU) of vitamin D every day. Postmenopausal women not using HT, anyone at risk of steroid-induced osteoporosis, and all men and women over 65 should aim for 1,500 mg of calcium and at least 800 IU of vitamin D daily. Getting enough vitamin D is just as important as getting adequate amounts of calcium. Not only does vitamin D improve bone health by helping calcium absorption, but it also may improve muscle strength. Scientists are continuing to study vitamin D ? which may also protect against certain types of cancer ? to determine the optimal daily dose, but it?s safe to take up to 2,000 IU a day.

Although many people get adequate amounts of vitamin D from sunlight, this may not be a good source if you live in high latitudes, if you're housebound, or if you regularly use sunscreen or you avoid the sun entirely because of the risk of skin cancer. Although vitamin D is present in oily fish such as tuna and sardines and in egg yolks, you probably don't eat these on a daily basis. Calcium supplements with added vitamin D are a good alternative.

As for calcium, dairy products are one, but by no means the only, source; almonds, broccoli, cooked kale, canned salmon with the bones, oats and soy products such as tofu are also rich in calcium. If you find it hard to get enough calcium from your diet, consider calcium supplements. Supplements are inexpensive and generally are well tolerated and well absorbed if taken properly. Sometimes calcium supplements can be constipating. If this is a problem for you, drink more water and try using a fiber supplement. In addition, check the type of calcium you're using. Calcium phosphate and calcium citrate tend to be less constipating.

Calcium and vitamin D supplements are most effective taken together in divided doses with food.

Other tips for prevention
These measures also may help you prevent bone loss:

• Exercise. Exercise can help you build strong bones and slow bone loss. Exercise will benefit your bones no matter when you start, but you'll gain the most benefits if you start exercising regularly when you're young and continue to exercise throughout your life. Combine strength-training exercises with weight-bearing exercises. Strength training helps strengthen muscles and bones in your arms and upper spine, and weight-bearing exercises ? such as walking, jogging, running, stair climbing, skipping rope, skiing and impact-producing sports ? mainly affect the bones in your legs, hips and lower spine. Swimming, cycling and machines such as elliptical trainers can provide a good cardiovascular workout, but because they're low impact, they're not as helpful for improving bone health as weight-bearing exercises are. 
• Add soy to your diet. The plant estrogens found in soy help maintain bone density and may reduce the risk of fractures, particularly in the first 10 years after menopause. 
• Don't smoke. Smoking increases bone loss, perhaps by decreasing the amount of estrogen a woman's body makes and by reducing the absorption of calcium in your intestine. The effects on bone of secondhand smoke aren't yet known. 
• Avoid excessive alcohol. Consuming more than two alcoholic drinks a day may decrease bone formation and reduce your body's ability to absorb calcium. There's no clear link between moderate alcohol intake and osteoporosis. 
• Limit caffeine. Moderate caffeine consumption ? about two to three cups of coffee a day ? won't harm you as long as your diet contains adequate calcium.